Psychosocial problems in children are common and disabling, resulting in a tremendous burden to children, families, ad society. The majority of children with psychosocial problems are managed in primary care settings, where new health care delivery systems are increasingly affecting management decisions by clinicians. Using a large sample of office-based primary care clinicians, this study will: 1) identify the types of treatment offered to children with psychosocial problems, 2) compare treatment choices among three different systems of care (managed care, fee-for-service, and Canadian national Health Insurance Plan), 3) determine the presence of modifiable barriers to mental health services across the systems of care, 4) distinguish the effect of these barriers on treatment provided from the effect of clinician and patient characteristics, and 5) evaluated selected outcomes of care among the three systems using a randomly selected sample of children with clinician-identified psychosocial problems. The study will collect information from parents and clinicians about more than 30,000 consecutive office visits by children 4 to 15 years to 450 primary care clinicians. Each clinician will enroll 75 eligible children seen for consecutive visits during a period of 2 to 15 weeks. The management strategies used by the clinicians in different systems of care will be examined for all enrolled children with identified psychosocial problems. A sample of 900 children randomly selected from those with identified psychosocial problems will be evaluated on specific measures completed by their parents/guardians at six months to compare outcomes among the systems of care. Participating clinicians are members of the two national office-based, primary care research networks in North America: the Ambulatory Sentinel Practice Network (ASPN) and the Pediatric Research in Office Settings (PROS) network. The large number of participating clinicians, the collective research, and the use of parent and clinician reports provide a unique opportunity to conduct this investigation. The research will contribute to the care of children with psychosocial problems by increasing knowledge of current primary care treatment practices for these children, and by examining the impact of different health care delivery systems on the receipt of treatment and selected outcomes. This information will be useful as clinicians and policy-markers evaluated the impact of administrative and financial barriers on mental health services for children in primary care settings.